#!/Library/Frameworks/Python.framework/Versions/3.5/bin/python3

x = int(input())

if 30 <= x:
    print("Yes")
else:
    print("No") x = int(input()) x int(input()) int input() input if 30 <= x:
    print("Yes")
else:
    print("No") 30 <= x 30 x print("Yes") print "Yes" print("No") print "No" x = int(input()) int(input()) x
#!/Library/Frameworks/Python.framework/Versions/3.5/bin/python3

x = int(input())

if 30 <= x:
    print("Yes")
else:
    print("No")
